3.
In a large mixing bowl, beat butter with an electric mixer for 30 seconds. Add sugar and vanilla; beat until well combined. Add eggs, one at a time, beating well after each addition.

4.
In a large measuring cup, combine applesauce and buttermilk. Alternately add applesauce mixture and flour mixture to butter mixture, beating on low speed after each addition just until combined.

5.
Spoon batter into prepared muffin cups, filling each about one-half to two-thirds full. Bake in preheated oven for 18 to 20 minutes or until a wooden toothpick inserted near centers of cakes comes out clean. Cool cakes in pans on wire racks for 10 minutes. Remove cupcakes from pans and cool thoroughly on racks.